Introducing to Superconducting Quantum Interference Device Project:
A Superconducting Quantum Interference Device (SQUID) is a very sensitive magneto meter, which is used for measuring extremely weak signals such as suddenly changes in human body electromagnetic energy fields. Its noise level is very low. For this measurement a device is used, which is known as “Josephson Junction”. It is made up of two superconductors and separated by a thin insulating layer and electrons pass through this device.
SQUID is used to measure a change of energy as much as 100 billion times of weak electromagnetic energy that passes through compass needle. In this each and every electron moves in opposite directions because current moves in two opposite directions. Generally SQUIDs have been using in testing purpose because its sensitivity, in engineering, medicine, and geological equipment measuring sensitive magnetic field energy, so it is used in these fields.
Electron-pair wave coherence and Josephson junction properties used by SQUID for measuring small magnetic fields. SQUID has a central element called as “ring”, which is made up of superconducting material with one or more weak links. This ring has 4-sides,2-opposite sides are weak links, whose critical current is much less than critical current of main ring. It produces less current density. There are 2-types of SQUID.
One is Direct Current (DC) SQUID, next one is Radio Frequency (RF) SQUID. In DC SQUID, when the external flux increased by the half integral multiple of Φ0 then the screening current direction changes every time. The superconducting ring becomes resistive and voltage appears across the junction. Whereas in RF SQUID is inductively coupled to resonant tank circuit.
When it is operated in resistive mode, then changes the inductance of tank circuit so resonant frequency changes, so easily measure these frequencies and losses appear as voltage across load resistance. The uses of SQUID are oil prospecting, earth-quakes prediction, mineral exploration, scanning, geothermal energy surveying, etc.
Download Final Year ECE Project Idea on Superconducting Quantum Interference Device .